Tescos had a similar deal like this last week in my local. They were selling off the boxes of 24 cans of Coca-Cola or Diet Coke for only £4.00. Just checked again today and they are selling them again at this fantastic price. Originally prices at £7.49, I came away with another box for myself.
Checked the date on them as well thinking they might be going out of date soon, but the expiry date is July 2010 so happy days. Not sure if this is nationwide or not but great deal if you can get your hands on them.
Works out to be only 17p per can.